Collaborative Research: Geophysical Study of Ice Stream Stick-slip Dynamics

合作研究：冰流粘滑动力学地球物理研究

• 批准号: 0944671
• 负责人: Douglas Wiens
• 金额: $ 17.39万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-08-15 至 2016-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944671&HistoricalAwards=false
• 关键词: Collaborative; Research; Geophysical; Study; Ice

Winberry/0944794This award supports a three-year study of the ongoing deceleration and stick-slip motion of Whillans Ice Stream (WIS), West Antarctica. Understanding the dynamic behavior of ice streams is essential for predicting the future of the West Antarctic Ice Sheet (WAIS). Despite being one of the best-studied ice streams in Antarctica, the surprising flow characteristics of WIS continue to demand interdisciplinary research. Recent estimates indicate that the WIS may stagnate within 50 years, resulting in a significant change to the mass balance of the Siple Coast sector of West Antarctica. The reasons for the ongoing stagnation are not well known, and are possibly linked (causally or coincidentally) to the stick-slip behavior. Our recent work on WIS stick-slip motion suggest that all slip events nucleate from a common location on the ice stream, suggesting that a relatively small (approximately 10 km in diameter) region of the exerts fundamental control over the flow of this large ice stream (100s of km long and 100 kilometers wide). We hypothesize that this is a region of increased bed strength and our measurements will address that hypothesis. We will deploy a series of GPS receivers and seismometers on the ice stream to accurately locate the nucleation region so that a comprehensive ground based geophysical survey can be conducted to determine the physical properties of bed at the nucleation point. The ground geophysical program will consist of reflection seismic and ice-penetrating radar studies that will better constrain the properties of both the hypothesized higher-friction nucleation zone and the surrounding regions. Slip events also generate seismic energy that can be recorded 100s of km away from the ice stream, thus, the GPS and seismometer deployment will also aid us in relating seismic waveforms directly with the rapid motion that occurs during slip events. The increased ability to relate rupture processes with seismic emissions will allow us to use archived seismic records to explore changes in the behavior of WIS during the later half of the 20th century. Broader impacts of this study include improved knowledge ice sheet dynamics, which remain a poorly constrained component of the climate system, thus, limiting our ability to predict the Earth's response to climate change. The scientific work includes the education of two graduate students and continued training of one post-doctoral scholar, thus helping to train the next generation of polar scientists. We will expose the broader public to polar science through interactions with the media and by take advantaging of programs to include K-12 educators in our field work.

Winberry/0944794该奖项支持对南极洲西部威兰斯冰流（WIS）正在进行的减速和粘滑运动进行为期三年的研究。了解冰流的动态行为对于预测西南极冰盖 (WAIS) 的未来至关重要。尽管 WIS 是南极洲研究最充分的冰流之一，但其令人惊讶的水流特征仍然需要跨学科研究。最近的估计表明，WIS 可能会在 50 年内停滞不前，导致西南极洲西普尔海岸地区的物质平衡发生重大变化。持续停滞的原因尚不清楚，可能与粘滑行为有关（因果或巧合）。我们最近对 WIS 粘滑运动的研究表明，所有滑移事件都从冰流上的一个共同位置成核，这表明相对较小（直径约 10 公里）的区域对这个大冰流的流动施加了根本控制。 （长100公里，宽100公里）。 我们假设这是一个床层强度增加的区域，我们的测量将解决这个假设。 我们将在冰流上部署一系列GPS接收器和地震仪，以精确定位成核区域，以便进行全面的地面地球物理调查，以确定成核点的地床物理特性。地面地球物理计划将包括反射地震和透冰雷达研究，这将更好地限制假设的高摩擦成核区及其周围区域的特性。滑动事件也会产生地震能量，可以在距冰流数百公里处记录下来，因此，GPS和地震仪的部署也将帮助我们将地震波形直接与滑动事件期间发生的快速运动联系起来。将破裂过程与地震发射联系起来的能力的增强将使我们能够利用存档的地震记录来探索 20 世纪下半叶 WIS 行为的变化。这项研究的更广泛影响包括提高对冰盖动力学的认识，冰盖动力学仍然是气候系统中约束较差的组成部分，因此限制了我们预测地球对气候变化反应的能力。科学工作包括培养两名研究生和继续培养一名博士后学者，从而帮助培养下一代极地科学家。我们将通过与媒体的互动，以及利用 K-12 教育工作者参与我们的实地工作的计划，让更广泛的公众了解极地科学。